The present invention related to a stem, groove and snap ring assembly and a method of forming a groove on a stem and assembling a snap ring. Methods of this general type are shown in the prior art patents 1,896,028, 2,464,622, 2,957,237, 3,686,743, 3,702,085 and 4,189,978. Prior methods of forming a groove about which a snap ring is inserted comprised milling the groove in the stem and then deforming the ends of the snap ring to force the snap ring to fit about the diameter of the stem and then closing the snap ring ends. Stem and snap ring assemblies and other caster retention mechanisms are shown in U.S. Pat. Nos. 3,755,852, 3,834,006 and 4,129,921.